Six Alabama Satsuma mandarin orchards (four conventionally sprayed and two unsprayed) were surveyed during 2005 and 2006 to determine the population dynamics of arthropod pests and their natural enemies. Twenty-eight arthropod pest species were encountered; the major foliage pests were citrus whitefly, Dialeurodes citri (Ashmead); purple scale, Lepidosaphes beckii (Newman); Glover scale, L. gloveri (Packard); and citrus red mite, Panonychus citri (McGregor). Two distinct population peaks were recorded for citrus whitefly at most locations. The most important direct sources of citrus whitefly mortality were parasitism by Encarsia lahorensis (Howard) and infection by the pathogenic fungus, Aschersonia aleyrodis Webber. In general, all stages of both scale insects (purple scale and Glover scale) were present in the orchards year-round, indicative of overlapping generations; however, the highest densities were recorded during the early season. Citrus whitefly, purple scale, and Glover scale were more abundant on leaves collected from the interior of the tree canopy than in the exterior canopy. Citrus red mite densities were highest in the spring, with populations declining at the start of the summer, and were more abundant in the exterior canopy than in the interior canopy. The most important natural enemies of citrus red mite were predatory mites belonging to several families, of which Typhlodromalus peregrinus Muma (Phytoseiidae) was the predominant species. Major differences were recorded in the relative abundance of different arthropod pest species in the orchards: citrus whitefly, purple scale, and Glover scale predominated in the unsprayed orchards, whereas citrus red mite infestations were more severe in the sprayed orchards. The results are discussed in relation to the possible effect of orchard management practices on abundance of the major pests.

Containerized `Owari' satsuma mandarin (Citrus unshiu Marc.) on Poncirus trifoliata `Flying Dragon' rootstock were exposed to one of two acclimation regimes (cold acclimated and unacclimated) and frozen in a computer-controlled freezer to five different low temperatures. Whole plant survival was measured and compared to the results of four leaf and stem injury assays. Acclimating plants in growth chambers at 20 °C day and 10 °C night for 14 days, followed by 15 °C day and 4 °C night for 14 to 21 days resulted in an 81% and 80% increase in leaf and stem survival, respectively, when frozen to a low of -8 °C. Electrolyte leakage and phenolic leakage assays effectively detected changes in percent leaf survival, but the TTC stain assay, using leaf disks, did not. Stem survival was best predicted by the TTC assay, using the phloem as the indicator tissue for survival. Electrolyte leakage and phenolic leakage were also reliable assays for predicting stem survival, although survival percentages were different at the same electrolyte leakage values reported in other studies. The callus growth assay accurately predicted survival for cold acclimated satsuma mandarin stems only. Chemical name used: triphenyl tetrazolium chloride (TTC).

Nine Satsuma citrus orchards (seven conventionally sprayed and two unsprayed) in southern Alabama were sampled (mainly leaf samples) for predacious mites at eight different sampling dates from March 2005 to February 2006. At least 29 species of predacious mites from nine families (Anystidae, Ascidae, Bdellidae, Cheyletidae, Cunaxidae, Erythraeidae, Eupalopsellidae, Phytoseiidae, and Stigmaeidae) were identified. In addition, six primarily fungivorous species from three families (Parasitidae, Tydeidae, and Tarsonemidae) were recorded. Predacious mites in the families Phytoseiidae (18 species) and Stigmaeidae (one species) were the most abundant. The dominant species were Typhlodromalus peregrinus (Muma) and Proprioseiopsis mexicanus (Garman) (Phytoseiidae), and Agistemus floridanus Gonzalez (Stigmaeidae). Phytoseiid mites were most abundant in the spring with populations declining at the start of the summer and remaining at very low levels through the fall and winter. Analysis of fruit, leaf and orchard ground cover plant samples collected in fall (October) 2005 showed greater abundance of phytoseiid mites on ground cover plants than on citrus fruit and leaves, suggesting that ground cover plants may serve as overwintering reservoirs for predacious mites. In general, predacious mites were relatively more abundant in the conventionally sprayed orchards compared with the unsprayed orchards, as were the two key phytophagous species, Panonychus citri (McGregor) and Phyllocoptruta oleivora (Ashmead). The results are discussed in relation to the potential of the dominant predacious mite species as candidates for biological control of key phytophagous mites on Alabama Satsuma citrus.

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Soil salinity management is a factor for successful production of pecan (Carya illinoinensis) in arid southwestern United States. An exploratory study was performed to evaluate the effect of various soil management practices on salt leaching in basin-irrigated orchards developed on alluvial soils (Torrifluvents, Entisols) of the middle Rio Grande Basin. The practices evaluated were ripping, minimum-till chiseling, and soil profile modification. For ripping, parabolic shanks were passed through the center section (4 to 8 ft wide) between each tree row to a depth ranging from 18 to 36 inches. Minimum-till chisels included 7- and 30-inch shanks, equipped with coulters to reduce break up of the ground surface. Soil profile modification consisted of trenching with a backhoe and profile mixing with a large excavator. The effectiveness of these methods was evaluated by measuring soil salinity and moisture in treated and untreated zones at 17 test sites. Both ripping and minimum-till deep chiseling helped improve salt leaching, and the effectiveness of salt leaching increased as working depths approach the thickness of the clayey layer. However, annual ripping of the center section of each tree row space may not provide wide enough zones to alleviate salt stress to the trees. Straight shanks prune but do not lift tree roots, thus appearing to be better suited for chiseling closer to tree rows. Soil profile modification was highly effective in leaching salts. From the view of minimizing soil aggregate destruction and of maintaining a leveled floor, minimum-till deep chiseling, followed by the use of sand-topdressing and minimum-till shallow chisels for maintenance may prove to be more desirable than conventional ripping, especially in soil types consisting of silty clay loam.